My problem child AR. WTF???

[Wake27]

Sometimes Gun Voodoo happens. Gun Voodoo is when something occurs, that wasn't previously an issue with no explanation. Do you have other AR's or friends with other AR's? When you say M855, do you mean MILSPEC M855 or some foreign clone ammo?

If so you need to isolate the issue. Step 1 is to replace the buffer with an H buffer. Then you need to get a GOOD BCG and put it into your upper and test it. Isolate the problem. Then I would put your BCG in the other upper and shoot it.

Pay particular attention to the carrier key, gas tube and gas rings. Although I will say that you can run an AR with only (1) gas ring on the bolt.

Do you not consider Centurion BCGs as good to go?

[Iraqgunz]

I don't think I said anywhere in my statement that they weren't good. But, things happen and no one is immune from a bad part. The BCG is also part of the gas system and what makes everything tick. So you need to sort out all the variables.

Do you not consider Centurion BCGs as good to go?

[F-Trooper05]

Sometimes Gun Voodoo happens. Gun Voodoo is when something occurs, that wasn't previously an issue with no explanation. Do you have other AR's or friends with other AR's? When you say M855, do you mean MILSPEC M855 or some foreign clone ammo?

If so you need to isolate the issue. Step 1 is to replace the buffer with an H buffer. Then you need to get a GOOD BCG and put it into your upper and test it. Isolate the problem. Then I would put your BCG in the other upper and shoot it.

Pay particular attention to the carrier key, gas tube and gas rings. Although I will say that you can run an AR with only (1) gas ring on the bolt.

Federal XM855 Green Tip.

I have plenty of AR's. Three BCM's, an LMT and a KAC. I can swap out parts all day long.

I'll try an H buffer and go from there. I switched from BCM to Centurian because the BCM I had was sucking and it was a replacement while BCM fixed theirs. I have plenty of spares laying around if the new buffer doesn't work. Just frustrating, as I really want this gun to be my primary, and so far it's just been the bane of my existence.

[Hmac]

As for the short stroking, obviously switching to an H buffer is the first step, which is no big deal. I'm just curious why now all of a sudden this would be necessary? I shoot 3 to 5 times a week, and suddenly (less than 24 hours after my last shoot) it goes tits up without any changes to the weapon system?

Yes. Trying the H buffer is a means of diagnosis, not definitive treatment. I was in the same boat. 5000 rounds of flawless function, all of sudden short stroking (manifesting itself as double feeds). Obviously, something broke.

[sadmin]

Happened to me as well on a BCM 14.5 mid. Sent it back and they resolved it. Gas port was leaking.


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[Digital_Damage]

As other have said.

Leaky gas port causing a short stroke is my guess. Is it a set screw, pinned or clamp on?

Inspect the gas block and make sure it is properly secured.

[F-Trooper05]

As other have said.

Leaky gas port causing a short stroke is my guess. Is it a set screw, pinned or clamp on?

Inspect the gas block and make sure it is properly secured.

It's a pinned FSB. If it's leaking gas this will be the gun's third time back to BCM. Fingers crossed.

[Shiz]

I switched from BCM to Centurion because the BCM I had was sucking and it was a replacement while BCM fixed theirs.

Did the malfs start happening close to this time frame?

[F-Trooper05]

Did the malfs start happening close to this time frame?

No the malfunctions with the BCM BCG were back in March. Changed to a Centurian BCG and haven't had an issue since (until Saturday). Honestly, I don't think the BCG is the issue. I think it's either the gas port is leaking (which I'm losing sleep over), or the buffer is too heavy (which I think would be way too easy of a fix considering the luck I've had with this gun).

[Iraqgunz]

How long have you had this upper and did you buy it direct? I have a hard time believing that they wouldn't just replace it. Can you please explain (I must have missed it) why it was sent back the other 2 times?

No the malfunctions with the BCM BCG were back in March. Changed to a Centurian BCG and haven't had an issue since (until Saturday). Honestly, I don't think the BCG is the issue. I think it's either the gas port is leaking (which I'm losing sleep over), or the buffer is too heavy (which I think would be way too easy of a fix considering the luck I've had with this gun).